Never mind that The Motorcycle Diaries is about the
youthful adventures of Ernesto Guevara before he became "Che", the
beret-wearing revolutionary whose iconic image would go on to adorn
countless T-shirts the world over.

Politics, it seems, is what everyone wants to talk about after
seeing Walter Salles's film. It's about the 1952 South American
road trip of Guevara, then a quietly spoken 23-year-old medical
student, and his ebullient friend Alberto Granado, a 29-year-old
biochemist.

Their eight-month trip, immortalised in books by both men, takes
them from their upper-middle-class homes in Buenos Aires into a
world the men barely knew existed. They travel by motorcycle, foot,
raft and truck, encountering some of the most beautiful and extreme
places on earth: the rugged Andes, Chile's merciless Atacama
Desert, and the Peruvian Amazon.

Along the way they meet the poor, the sick and the dispossessed.
It's through these encounters with "the people" that Guevara feels
the first stirrings of desire for radical change.

Taking on even one part of the life of a man among the "icons of
the century" was always going to be difficult. Even The
Motorcycle Diaries' executive producer, Robert Redford,
predicted that Guevara would be "a tricky subject".

He was right. Some critics have argued that Salles has made
nothing more than a good-looking travelogue that provides a
simplistic view of Guevara's political conversion. Others enjoy
that Guevara's controversial politics, which led to his death, take
a back seat to the jaw-dropping vistas of South America and the
pleasure of watching Mexican heart-throb Gael Garcia Bernal on
screen as Guevara.

None of the debate surprises Salles.

Best known for 1998's Central Station, the Brazilian
director says that "the fascinating part of this journey is to see
how, depending on the latitude, different people can say the film
is excessively political or not political enough, which means we
found a good equilibrium at the end of the day".

"The film came out in the United States when political debate
was at its peak during the presidential campaign," he says.

"There were reviews that said the film ideologised the book,
that it's overtly more political than the book.

"Then there were voices in other latitudes that said, 'Well, no,
the film doesn't politicise enough its subject.' This is very
telling of what we tried to do, which is never to be didactic or
dogmatic about the subject but to find, really, the true
humanity.

"[We wanted] to be able to look at this story that preceded
history with a capital H without trying to impose a point of view
on Che. Too many people have judged Guevara for us to do it; we
just wanted to try to understand what he came from."

Salles was fortunate to have the help of Guevara's amigo
Granado, who at 82 still lives in Cuba where he established a
medical school.

"Alberto has an extraordinary memory that allowed us to
understand so many passages of this story that were somehow unclear
to us," Salles says.

The director used a close-up of the octogenarian for the final
scene in his film.

He says that even as an old man Granado still displays the
humour evident throughout the journal he kept while on the road
with Guevara.

"He came for the premiere of the film in Cannes - he wasn't
granted a visa to come to the Sundance premiere in January," Salles
says.

"And after a 15-minute standing ovation centred on him actually
at the end of the screening at the Palais, he turned to Gael and me
and said, 'Man, I have so much emotion that if I was 20 years
younger I think I'd be dead by now.'

"There you have Alberto in all his splendour, and he still has
the capacity to laugh about himself and about what is happening to
him.

"He also came out and said to Gael, 'Man, I'm afraid to wake up
from this and to find myself again at twentysomething years old
still selling condoms in a pharmacy in Argentina,' which was what
he was doing prior to the journey."

Granado wasn't the only one still around 50 years on who could
help Salles with details of the story. The director retraced the
journey twice before filming started to scout for locations and for
locals to play the people who Guevara and Granado meet on the
road.

"As we were progressing into the heart of the continent, we were
meeting people who were in their 70s or late 60s who had actually
known the two travellers," Salles says.

"We met five ex-patients of the San Pablo leper colony who
decided to take part in the shoot, so they are the ones you see
when the men arrive at the colony. They helped us to understand how
that environment was organised and the social implications of
that.

"[There were] some other very interesting coincidences. As we
were shooting the scene with Ernesto at the dance hall in Temuco,
Chile, where he escapes the fury of the mechanic whose wife he was
actually charming, we discovered that the woman who was at the
centre of that confrontation lived next door to the place where we
were filming.

"So The Motorcycle Diaries was one of those films where
you really had a surprise per day."

Salles went to extraordinary lengths to recreate the spirit of
discovery that Guevara and Granado express in their accounts of the
journey.

He knew the route well by the time shooting started, but he says
"we knew that we should never bring actors to this process because
they had to be seeing what they would discover as we were shooting
the film for the first time.

When we were shooting in Machu Picchu, they are really looking
at Machu Picchu for the first time and there's a sense of wonder
that comes from that."

Salles says production was also helped by the reality "that
Latin America has changed so little in 50 years".

"We were not shooting a documentary - we were all aware of that
- but we had to seek the same level of truth that documentary can
bring to the audience," he says.

"That was achieved by the fact we were really discovering things
as we were progressing. The actors were losing weight as we were
getting further and further into the heart of the continent."

Rodrigo de la Serna, the little-known Argentine actor who plays
Granado and is the real-life second cousin of Guevara, put on 15
kilograms for the part.

"They knew more about that pan-American reality than they knew
at the beginning, and they conveyed that through their eyes."

After years of researching, filming and talking about Guevara,
what conclusion has Salles reached about his fellow Argentine?

He laughs then finally says: "He is a much more polyphonic
character [than most people realise]. There are so many
Guevaras.

"If you read the three main biographies that exist on him, they
each defend a different point of view, a little bit as if you were
in Kurosawa's Rashomon.

"And this is what I take from the end of these five years of
researching the subject - that there's no end to it."